The invention relates generally to fiber optic cable connectors, strain relief of boots for such connectors, and methods of assembling such connectors. More particularly, the invention is directed to a fiber optic cable connector having a strain relief boot that can be easily attached to and removed from an assembled fiber optic assembly, as well as, related strain relief boot designs and methods of assembly.
Various types of connectors have been developed for connecting optical cables to optical system components such as active or passive optical devices, or to other optical cables. Numerous factors influence the design of such connectors, including the diameter and makeup of the optical fiber used in the cable, the environment into which the cable and connector are placed, the space available for connection, and the number of connections required in a given location, to name but a few. Several of the optical cable connectors currently in common use include SC, DC, Unicam, LC, FC, ST, MTP, MU, MTRJ, and similar connectors.
Many such connectors are attached to a flexible member, commonly known as a strain relief boot, on the end of the connector opposite the terminated fiber. As the name suggests, the strain relief boot reduces strain on the fiber optic cable and connector, such as, for example, during pulling on the cable, so as to avoid violating the minimum bend radius of the optical fiber within the cable. Such bending could lead to attenuation and even breakage of the optical fiber or other damage to the connector.
Boots typically are annular with one wider end and one narrower end. The fiber optic cable passes through the boot with the wider end typically attaching to the connector and with the cable exiting the narrower end. In connectorizing a fiber optic cable, the first step is typically sliding a boot over the cable from the end being connectorized. Afterwards, various other parts such as a crimp band, a crimp body, a ferrule, a ferrule holder, a connector housing, etc., are attached to the end in sequence while various manipulations are performed to the cable and the parts. Once most if not all of the connector assembly steps are completed, the boot is slid along the fiber optic cable until the boot engages and is secured to the connector.
While connectorizing a fiber optic cable is typically not a complicated or time consuming task for a trained technician, a certain amount of time is required to properly achieve such connectorization. If one forgets to attach the boot before some of the connectorization steps are performed, the fiber optic cable will have to be cut and all of the steps will have to be performed again, thereby causing delay and a waste of otherwise acceptably assembled parts. Further, if a boot were to become damaged, one would have to recut and reconnectorize the cable in order to replace just the boot. Also, if one were to wish to change the type of boot on the connector, one would also have to recut the cable and reconnectorize it. As compared to many of the connector parts, the boot is not subject to high manufacturing tolerances and precise assembly requirements. Thus, to replace a xe2x80x9clow tolerancexe2x80x9d part of a connector assembly, more precisely manufactured and assembled parts must be discarded and replaced. As can be seen, in each of these scenarios, potentially acceptable connector parts are discarded, and additional effort and expense is required to reconnectorize the cable in order to add or change the boot.
This invention addresses the above needs by providing a strain relief boot for that is configured to be easily installed after a connector and an fiber optic cable, ribbon, or other device have been assembled in a fiber optic assembly. Further, the strain relief boot of this invention provides means for repeatedly removing and reinstalling the strain relief boot to the fiber optic assembly without damage to the connector or to the fiber optic cable, ribbon, or other device of the fiber optic assembly. While the embodiments below describe the fiber optic assembly having a connector and a fiber optic cable, this is not to be limiting and should be understood that alternate embodiments of the fiber optic assembly may have a connector and a fiber optic ribbon or an optical device.
The strain relief boot includes an extending member having a first end configured for attachment to the connector, a second end opposite the first end, and a passageway extending from the first end to the second end configured to receive a portion of the fiber optic cable and a portion of the connector. The extending member is flexible so as to be bendably deflectable along with the portion of the fiber optic cable relative to the connector. Further, the extending member includes attachment means for attaching the extending member to the connector and to the portion of the fiber optic cable after the connector and the fiber optic cable are positioned together. In alternate embodiments, the extending member is rigid so as to not bend.
The attachment means may include an overmolded extending member configuration, or a slit extending from the first end to the second end in communication with the passageway, the slit configured for passing at least the fiber optic cable into the passageway in a radial direction. The attachment means may alternatively include two parts configured to be attached together to form the passageway therebetween, at least one hinge formed unitarily with and between the two parts, an adhesive, a hot melt, an ultrasonic weld, and/or mating elements disposed on the extending member. The attachment means may also include a coil element extending member configuration and a collar disposed at an end of the coil element.
Also, the extending member may include two parts configured to be attached together to form the passageway therebetween. The extending member may include at least one hinge formed unitarily with and between the two parts, or the two parts may be formed nonunitarily. The two parts may attached together at least partially by an adhesive, by a hot melt, by an ultrasonic weld, by mating elements disposed on each of the two parts, by an interference fit, by a snap fit, or by other suitable techniques.
The extending member may include a coil element, and the coil element may have two ends. The extending member may include a collar disposed at one of the ends. The collar may include a first part and a second part, the second part being movable relative to the first part to open or close a slit extending axially along the collar.
The collar may be configured to be attachable to or removable from the fiber optic cable and the connector when the slit is opened, and the collar may be configured to secure the extending member to the fiber optic cable and the connector when the slit is closed.
The extending member may be at least partially curved along its length, and the extending member may be configured so that a curvature of the extending member has a radius of curvature greater than a minimum bend radius of the fiber optic cable. The extending member may curved from about 179 degrees to about 90 degrees. Alternatively the extending member may be substantially straight or about 180 degrees.
The extending member may include a tapered portion having an outer diameter that decreases in the direction of the second end of the extending member. The extending member tapered portion may taper uniformly or nonuniformly. The extending member may define openings extending substantially radially, and the extending member may be configured to be rotatable relative to the connector.
According to another aspect of the invention, a method of assembling a connectorized end of a fiber optic cable is provided, the method including the steps of preparing the end of a fiber optic cable for connectorizing, connectorizing the fiber optic cable by attaching a connector to the end of the fiber optic cable, and attaching a flexible strain relief boot to the connector and a portion of the fiber optic cable after the connectorizing step.
The attaching step may include overmolding the strain relief boot. Alternatively, the attaching step may include sliding at least the fiber optic cable through an opening in the strain relief boot into a passageway extending through the strain relief boot. The attaching step may also include attaching two parts of the strain relief boot together to enclose at least a portion of the fiber optic cable within a passageway extending through the strain relief boot. This may be accomplished by attaching the two parts using an interference fit, a snap fit, an adhesive, a hot melt, an ultrasonic weld, and/or mating elements disposed on the two parts. Further, the two parts may be formed unitarily with a hinge, and attaching the two parts may include pivoting the two parts at the hinge so as to provide contact between the two parts.
The attaching step may also include threading a coil around the fiber optic cable, opening a collar attached to the coil, threading the fiber optic cable through the opened collar, and closing the collar after the fiber optic cable has been threaded through the collar.
The attaching step may also include the substeps of placing the strain relief boot around the fiber optic cable spaced from the connector, and sliding the strain relief boot along the fiber optic cable into engagement with the connector. Alternately, the attaching step may include placing the strain relief boot simultaneously around the connector and the fiber optic cable.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.
For better understanding of this invention, reference is made to the following description taken in conjunction with the accompanying drawings.